Novel cyan-forming couplers



innate United SW68 Patent O" 2,976,146 NOVEL CYAN-FORMING COUPLERSIlmari F. Salminen and James A. Van Allan, Rochester,

N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporationof New Jersey No Drawing. Filed Nov. 28, 1958, Ser. No. 776,699

7 Claims. (Cl. 96-55) This invention relates to photographiccolor-forming or coupling compounds and their use in developercompositions for developing colored photographic images.

The use of color-forming compounds which react with the developmentproduct of primary aromatic amino developing agents to form color imageson photographic development is well known and has been the subject ofnumerous prior patents. The dyes formed in this way usually areinsoluble in water and in the ordinary photographic developing andfixing baths, although the silver images formed simultaneously with themduring the photographic development may be removed from the photographiclayer to leave pure dye images in the layer. The coupler compounds usedin this way may be added to the developing solution or in certain casesmay be incorporated in the photographic layer prior to exposure.

The coupler compounds generally used for subtractive color photographyform, upon color development, yellow, magenta or cyan dyes. In order tobe useful for color photography, the dyes produced upon colordevelopment must have certain desirable light transmission orspectrophotometric characteristics. Thus, ideally, the cyan orblue-green dye should absorb red light completely and transmit blue andgreen light completely. It should retain these transmissioncharacteristics over a long period of time and should withstandreasonable exposure to heat and light without appreciable fading or lossof these light transmission characteristics. The other dyes should alsoexhibit selective absorption and transmission characteristics.

Many of the available couplers, however, have been found not to producedyes having these characteristics to the desired degree.

Additionally, if the coupler compounds are to be incorporated indeveloping solutions they must be surficiently soluble and reactive sothat the amounts used will produce sufficiently high dye densities inthe resulting photographic image.

It is therefore an object of the present invention to provide a novelclass of cyan-forming couplers for use in color photography. A furtherobject is to provide new and improved color-forming couplers which areuseful in color developer solutions containing a primary aro matic aminodeveloping agent. A still further object is to provide new couplerswhich upon color development with primary aromatic amino developingagents produce cyan dye images Which combine good light transmissioncharacteristics and good dye stability to an unusual degree. Otherobjects Will become apparent from the description of our invention.

These and other objects are accomplished by means as describedhereinafter.

We have discovered that certain phenols and a-naphthols having aheterocyclic group in the 2-position give indoaniline dyes having goodlight transmission characteristics and excellent dye stability. The goodtransmission characteristics are unexpected since previous experiencewith other phenols and u-naphthols having hetero- Patented Mar. 21, 1961cyclic groups in the 2-position would lead one to expect dyes withabsorption maxima in the near infrared region of the spectrum. Thecouplers of Frohlich et al. U.S. Patent 2,373,821, for example, producedyes that have a specially high light absorption in the infrared regionof the spectrum with maximum light absorption in the 700 to 730 m range..Our couplers produce dyes that have maximum light absorptions in theregion of wavelengths from 596 to 680 mu.

In accordance with the invention, we use as cyanforming couplers,compounds of the formula:

lit-C N i e wherein Z is a combination of non-metallic atoms necessaryto form either unsubstituted or substituted heterocyclic triaza rings;Ar--OH is a phenol or an a-naphthol group substituted at the carbon inthe 2-position with the triaza ring and at the carbon in the 4-positionwith R which may be a hydrogen atom, a halogen atom such as a chlorineatom, or a sulfo radical. When R is a sulfo group on an a-naphtholnucleus, the sulfo group is usually attached on the carbon in the 6position as Well as the carbon in the 4 position.

More specifically, the preferred compounds of our invention have theformula:

aromatic amino. developing agents, sodium 'sulfite and the otherchemicals commonly used in color developer solutions.

Color developers containing our couplers develop ,ex-

posed photographic emulsions to produce cyan dyeimages having goodspectrophotometric characteristics-with maximum light absorption intheregion of wavelengths from 680 to 596 11111.. These goodspectrophotometric characteristics are retained by the dye images overlong periods of time. The dye images from our couplers are more's'tableupon exposure to heat and light than are the dyes from some commerciallyused couplers. These very desirable characteristics make our couplersparticu-' larly valuable for use in color photography.

The compounds employed according to our invention can be prepared by thereaction of equal molar quantities of heterocyclic hydrazine withphenyl-l-hydroxy 2-naphthoate or phenyl-l-hydroxy-2-benzoate. p

The invention is illustrated by the following typical compoundsembodying the invention although it willbe understood that the inventionis not limited to the particular embodiments described nor to thcirf use asillustrated unless otherwise specifically indicated. t

3 EXAMPLE A The following compound embodies the invention:

I II c CouplerI 3- (1-l1ydroxy-2-nnphthyl -8-thia-1,2,Ba-triazacyclopent[ed-indent:

A mixture of 16.5 g. of 2-hydrazinobenzothiazole, 26.4 g. ofphenyl-l-hydroxy-Z-naphthoate in 100 ml. of amethyl naphthalene wasrefluxed for 3 hours, distilling off the water and phenol as formed. Thereaction mixture was then cooled, and filtered. The crude product thusobtained was crystallized from butanol to give 21 g. of product, M.P.258-9" C.

Analysis calculated for C I- N 51 C, 68.0; H, 3.5. Found: C, 68.3; H,3.4.

EXAMPLE B Another compound embodying the invention is:

Coupler II 3-(1-hydroxy-4,6-disu1fo-2-nahthyl)-8-thia-1,2,3a-trlazaeyclopent Pahndene which was prepared byheating five parts of Coupler I and fifteen parts of concentratedsulfuric acid on a steam bath for four hours. The solution was cooledand poured into water, causing precipitation of Coupler II, which wasthen filtered, washed with distilled water, and dried. Analysiscalculated for C H O N S C, 45.3; H, 2.3. Found: C, 45.8; H, 2.5.

EXAMPLE C Another compound embodying the invention is:

s I f OH Coupler III 3- (1-hydroxy-2-pheny1)-8-thia-1,2,3a-triazacyc1opent[a1indene which was prepared by the sameprocedure as was used for Coupler I by substitutingphenyl-1-hydroxy-2-benzoate for phenyl-l-hydroxy-2-naphthoate. CouplerHI melted at 284 C.

Analysis calculated for C I-I ON S: C, 62.8; H, 3.4. Found: C, 62.6; H,3.6.

EXAMPLE D Another compound embodying the invention is:

50:11 Coupler IV3-(2-hydroxy-5-sulfophenyl)-8-thla-1,2,3a-trlazacyclopent [alindenewhich was prepared by sulfonating Coupler III by the same procedure thatwas used to prepare Coupler II from Coupler 1.

Analysis calculated for C H O S N C, 48.4; H, 2.6. Found: C, 47.8; H.3.3.

4 EXAMPLE E Another compound embodying the invention is:

Coupler V l-(l-hydroxy-Z-naphthyl) -2,3,9h-triazabenz[g1 indene whichmay be prepared by the following process which we used.

A mixture of Z-hydrazinoquinoline and 27.0 g. ofphenyl-l-hydroxy-Z-naphthoate in ml. of trichlorobenzene was refluxedfor 3 hours; The phenol and water were removed as formed. The reactionmixture was cooled and the precipitated product was collected byfiltration and crystallized from 1,2,4-trichlorobenzene to give 24 g. ofproduct (77% M.P. 289 C.

Analysis calculated for C H ON C, 77.1; H, 4.2. Found: C, 77.3; H, 4.0.

EXAMPLE F Another compound embodying the invention is:

Analysis calculated for C H ON CI: C, 69.9; H, 3.2. Found: C, 69.9; H,3.4.

EXAMPLE G Another compound embodying the invention is:

.mljjr Coupler VII 1- (1-hydroxy-,G-disulfo-Zmaphthyl)-2,3,9b-trlazabenz [g] lndene which was prepared by sulfonating CouplerV in the same manner that Coupler II was prepared from Coupler I.

Analysis calculated for C H O N S C, 50.0; H, 2.5. Found: C, 51.0; H,2.5.

ridine for Z-hydrazinoquinoline.

. EXAMPLE H Another compound embodying the invention is:

Coupler VIII 1-(1-hydroxy-2-pheny1)-2,3,9b-trlazabenz[glindene which wasprepared in the same manner as Coupler V with the substitution ofphenyl-l-hydroxy-2-benzoate in place of phenyl-1-hydroxy-2-naphthoate.The coupler had a melting point 290 C.

Analysis calculated for C H ON C, 73.5; H, 4.2. Found: C, 73.5; H, 4.5.

EXAMPLE I Another compound embodying the invention is:

Analysis calculated for C H O N S: C, 56.2; H, 3.24. Found: C, 56.4; H,3.10.

EXAMPLE J Another compound embodying the invention is:

Cou let X 3- (1-hydroxy-2-napht liyl) -l,2,3a-triazaindene which wasprepared by the same procedure used to prepare Coupler V with thesubstitution of Z-hydrazinopy- The Coupler X had a melting point of238-9" C.

The analysis calculated for C H ON was: C, 73.5; H, 4.4. Found: C, 73.7;H, 4.5.

The objects of this invention can be accomplished with othercyan-forming couplers as defined herein having a nucleus consisting of aphenol or an a-naphthol group connected through the carbon in its2-position to a triaza ring substituted with the combination ofnonmetallic atoms necessary to form either substituted or unsubstitutedrings consisting of pyridine, quinoline or benzothiazole. Our couplersare characterized by producing, upon color development, indoaniline dyeshaving unexpectedly good spectrophotometric properties which arevaluable for color photography, and are also characterized by formingupon color development dyes having unusually good stability to both heatand light.

All of our couplers are further characterized by having good solubilityin primary aromatic amino color developers containing the sulfite of analkali metal such as sodium sulfite, and the-other constituents, andaddenda commonly found in color developers.

Our couplers are designed for use in processes in which the coupler isincorporated in the developing solution such as those described inMannes and Godowsky U.S.

'Patent 2,113,329, granted April 5, 1938, or Mannes,

Godowsky and Wilder U.S. Patent 2,252,718, granted August 19, 1941.

The following composition illustrates a typical developer solution inwhich our couplers are used.

EXAMPLE K Solution A: Gms. p-Amino diethylaniline hydrochloride 2 Sodiumsulfite 5 Water to 950 cc.

Solution B:

Coupler V gms 2.0 Sodium hydroxide do 0.7 BA Alcohol cc 50 ments thatthe color developer must satisfy. For example, any of the Well-knownantifoggants, silver halide solvents, competing couplers, competingdevelopers and other constituents such as potassium bromide, sodiunrcarbonate used in developer solutions may be incorporated in developercompositions containing our couplers. Any color-forming developercontaining a primary aromatic amino group may be used. These ineludedevelopers having two primary amino groups as well as those having oneof the amino groups-substituted or having substituents in the ring suchas alkylphenylenediamines and alkyl toluylene diamines. These compoundsare usually used in the salt form such as the hydrochloride or thesulfate which are more stable than the amines themselves. Suitabledeveloping agents are diethyl-p-phenylene-diamine hydrochloride, mono--methyl-p-phenylenediamine hydrochloride, dimethyl-pphenylenediaminehydrochloride and 2-amino-5-diethylamino-toluene hydrochloride. Thep-arninophenols and their substitution products may also be used Wherethe amino group is unsubstituted. All of these developers have anunsubstituted amino group which enables the oxidation products of thedeveloper to couple with the color-forming compounds to form a dyeimage.

Our development process can be employed for th production ofcyan-colored images in light sensitive silver halide emulsion layerscontaining gelatin or other carrier such as collodion, organic esters ofcellulose or synthetic resins. The carrier may be supported by atransparent material such as glass, a cellulose ester or anon-transparent reflecting medium such as paper or an opaque celluloseester. The photographic light sensitive emulsion may be coated as asingle layer on the support or as superposed layers on one or both sidesof the support. The superposed layers may be differently sensitized.Usually the cyan-forming layer is used in conjunction with yellow andmagenta image forming layers for the purpose of natural colorphotography by the subtractive process. The superposed cyan, yellow andmagenta image forming layers may be arranged in any order on thesupport. 1

The following example illustrates a typical way. in which our couplersare used in color developers for de veloping cyan dye images in exposedsilver halide emulsion layers.

EXAMPLE L A film coated with an ordinary photographicsilver bromoiodideemulsion for color photography was exposed G. 2,4-diarnino phenylhydrochloride Sodium sulfite 50 Potassium bromide 5 Water to 1 l.

The film was exposed through the base for about 20 seconds to 100 footcandles of light through a red filter transmitting light of longerwavelength than 6400 A.U. to expose the emulsion layer. Following thisexposure, the film was developed for 12 minutes in the color formingdeveloper given in Example K, washed and then the silver image and theresidual silver halide was removed by treating the film for 5 minutes ina potassium ferricyanide potassium bromide bleach, washing for 5 minutesand fixing in a hypo fixing bath for 5 minutes. After a minute finalwash, the film was dried. The result was a positive dye image having a Avalue of 676 m EXAMPLE M A negative cyan dye image having a A value of676 m was produced in another sample of the film used in Example L.After being exposed to an image as in Example L, it was developed for 12minutes in the color developer, Example K, followed by the subsequenttreat ment used in Example L to remove the silver and silver halideimages from the emulsion.

The cyan dye images produced in Examples L and M were found not only tohave a very desirable x max. value but to have excellent stability uponexposure to heat and light. For example, the most dense areas of the dyeimage formed in Examples L and M changed only 0.02 density unit to redlight as a result of one weeks storage at 140 F. and 75% relativehumidity. A 50 hour exposure of this cyan dye image in a xenonfadeometer produced only a 0.12 density unit change.

All of our couplers can be incorporated in developer solutions such aswe have described in Example K and used to develop cyan dye images inphotographic silver halide emulsions. Cyan dye images produced bydevelopers containing our couplers not only have desirablespectrophotometric properties for use in color photography but are alsostable upon exposure to heat and light. The following table illustratesthese properties as shown by typical examples:

Our couplers have demonstrated good solubility when incorporated indeveloper solutions. They couple actively with the oxidized developingagent to form cyan dye images in the exposed silver halide emulsionlayer upon development.

The novel class of cyan-forming couplers of our invention describedhereinabove has very desirable properties which make them unusuallyvaluable for color photography. All of our couplers react with theoxidized primary aromatic amino developing agents during colordevelopment to produce good cyan colored dyes having very desirablespectral properties characterized by )t max. values in the range of 680to 596 m These characteristics are unexpected since previous experiencewith other phenols and a-naphthols having heterocyclic groups in the2-position would lead one to expect the dyes produced from them wouldhave absorption maxima in the near infrared region of the spectrum, andthus be greenishcyan in color. Furthermore, the excellent stability toheat and light shown by cyan dyes produced from our couplers makes themespecially valuable for use in color photography. Our couplers arereadily soluble in color developers and have good reactivity with thedeveloping agents used.

The invention has been described in detail with particular reference topreferred embodiments thereof but it will be understood that variationsand modifications can be effected Within the spirit and scope of theinvention as described hereinabove and as defined in the appendedclaims.

We claim:

l. A cyan color-forming photographic developer comprising a primaryaromatic amino developing agent and a coupler compound having theformula:

and

wherein Z is a combination of non-metallic atoms necessary to form aring selected from the group consisting of the pyridine ring, thequinoline ring, and the benzothiazole ring and R is a member selectedfrom the group consisting of hydrogen atoms, chlorine atoms and sulforadicals.

2. A cyan color-forming photographic developer comprising a primaryaromatic amino developing agent and the coupler3-(l-hydroxy-Z-naphthyl)-8-thia-l,2,3a-triazacyclopenta [a]indene.

3. A cyan color-forming photographic developer comprising a primaryaromatic amino developing agent and the couplerl-(l-hydroxy-Z-naphthyl)-2,3,9b-triazabenz [g]indene.

4. A cyan color-forming photogaphic developer comprising a primaryaromatic amino developing agent and the coupler1-(1-hydroxy-4-chloro-2-naphthyl)-2,3-9b-triazabenz[g]indene.

5. A cyan color-forming photographic developer comprising a primaryaromatic amino developing agent and the coupler1-(1-hydroxy-4,6-disulfo-2-naphthyl)-2,3,9btriazabenz[g]indene.

6. A cyan color-forming photographic developer comprising a primaryaromatic amino developing agent and the coupler 3-(l-hydroxy-Z-naphthyl) -l,2,3 a-triazaindene.

7. The method of producing a colored photographic image in a silverhalide emulsion layer which comprises exposing said emulsion anddeveloping it with a primary aromatic amino developing agent in thepresence of a coupler compound of the formula:

I 2,976,146 9 19 a d sary to form a ring selected from the groupconsisting OH of the pyridine ring, the quinoline ring, and the heme- CN consisting of hydrogen atoms, chlorine atoms and sulfo I l 5 radicals.

\ References Cited in the file of this patent UNITED STATES PATENTSthiazole n'ng and R is a member selected from the group wherein Z is acombination of non-metallic atoms neces- 10 2,353,754 Peterson July 18,1944.

1. A CYAN COLOR-FORMING PHOTOGRAPHIC DEVELOPER COMPRISING A PRIMARYAROMATIC AMINO DEVELOPING AGENT AND A COUPLER COMPOUND HAVING THEFORMULA: